66358661 has 2 divisors, whose sum is σ = 66358662. Its totient is φ = 66358660.

The previous prime is 66358613. The next prime is 66358673. The reversal of 66358661 is 16685366.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 62710561 + 3648100 = 7919^2 + 1910^2 .

It is a cyclic number.

It is not a de Polignac number, because 66358661 - 2²² = 62164357 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66358601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33179330 + 33179331.

It is an arithmetic number, because the mean of its divisors is an integer number (33179331).

Almost surely, 2^66358661 is an apocalyptic number.

It is an amenable number.

66358661 is a deficient number, since it is larger than the sum of its proper divisors (1).

66358661 is an equidigital number, since it uses as much as digits as its factorization.

66358661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 155520, while the sum is 41.

The square root of 66358661 is about 8146.0825554373. The cubic root of 66358661 is about 404.8547179967.

The spelling of 66358661 in words is "sixty-six million, three hundred fifty-eight thousand, six hundred sixty-one".